Unfortunately, that's a very vague question. The XO talks over 802.11b/g which is either 11 or 54 mbps (that's bits). But since all the points that transmit share the same frequency channel, it's 54mpbs total to be shared among all your points.

On the other side of the picture, the bandwidth you need is determined by how much you use (if it is a lot less than how much is potentially available). For example, if all you are doing is sending text IMs, the it's a pretty low data rate. On the extreme side of that, say you turn on your computer and you don't do anything at all. Well, there are still some packets flying around to ensure the connection stays active, a tad bit of overhead.

So from one perspective, if your maxing out your throughput, then 100 XOs and 100 dells take up the same amount of bandwidth: your available max of 54mbps. From the other perspective, they are taking up the same amount of bandwidth: sitting there idle with some minimal overhead packets flying around to make sure everybody is still connected.

In other words, depending on how you are defining "bandwidth", you either mean how much you are using, or you mean what radio/protocol you are using. How much data you are using is irrelevant of XO or dell. As for the radio/protocol, The XO is 802.11b/g. What is your dell?